This research project is concerned primarily with analysing the plexiform layers of various vertebrate retinas and synaptic areas elsewhere in certain visual systems with a combination of 1) light microscopy of Golgi-impregnated tissue; 2) electron microscopy of tissue fixed by standard methods; and 3) when practical, electron microscopy of Golgi-impregnated tissue. Specific projects include: 1. A study of the inner and outer plexiform layer connections in a number of vertebrate retinas (i.e. toad, rabbit, monkey, fish, and ground squirrel) to see if a general statement can be made concerning neural connections in various retinas. 2. A study of synaptic areas in the visual systems of selected, physiologically interesting, invertebrates.